Commercial spraying equipment is well known. The present invention relates to commercial/professional spray systems mounted on or towed by tractors or special purpose vehicles. Such spray systems can be used for applying pesticides and fertilizers, for example. Typically a concentrated chemical is mixed with water in a large tank (approx. 100 gallons) which is carried or towed by the vehicle. A sprayer pump, usually powered off of the vehicle prime mover, pressurizes the solution and provides it to one or more spray booms, each of which carries a plurality of spray nozzles which collectively direct the solution, under pressure, toward the ground. The present invention will be discussed primarily in terms of spraying pesticides, but it should be noted that by no means is the present invention limited to pesticide sprayers.
During operation of a commercial spray system, the air surrounding the spray vehicle and the available breathing air for the operator can become contaminated with pesticides, pollen and other fine dusts and vapors. The level of contamination and the seriousness of the problem depend on a variety of factors including the type of solution being dispensed, the wind speed and direction, the speed of the spray vehicle, and the ambient dust levels.
One proposed solution to the contaminated air problem is to provide a filter mask (i.e., a breathing mask that covers the mouth and nose) to each operator of the equipment. Face masks filter out some substances, e.g., dust and pollen, to some degree, but they are not as effective with other substances, e.g., pesticides and ammonia fumes. And getting a breathing mask to fit properly and comfortably is difficult, at best. Also, operators might forget to wear their breathing masks.
Another proposed solution to the contaminated air problem is to use a completely closed cab. Such cabs are completely enclosed by glass windows but usually have a ventilation system for pressurizing the cab in an attempt to keep fumes and dust out of the cab. While useful in some situations, a completely enclosed cab has its own set of problems. For one thing, some operators simply do not like being completely enclosed by glass. Also, when the operator opens the door of a closed cab, dust and fumes can, in some situations, literally pour through the doorway into the cab. Once the inside of the cab becomes contaminated, it may be some time before the ventilation system adequately "scrubs" the air, given the fact that such a ventilation system is typically designed to operate in a dirty outside air environment rather than a dirty inside air environment. Of course, in some conditions a closed cab can also become excessively stuffy and warm, even if the glass is tinted and the ventilation system is normally sufficient to the task.
The present invention is designed to improve upon the face mask and closed cab "solutions" to the contaminated air problem.